On Fri, Jul 10, 2015 at 10:21 AM, Uros Bizjak <ubiz...@gmail.com> wrote: > On Fri, Jul 10, 2015 at 7:10 PM, H.J. Lu <hjl.to...@gmail.com> wrote: >> On Fri, Jul 10, 2015 at 9:30 AM, Uros Bizjak <ubiz...@gmail.com> wrote: >>> On Thu, Jul 9, 2015 at 12:54 PM, H.J. Lu <hjl.to...@gmail.com> wrote: >>>> Indirect sibcall with register arguments is OK when there is register >>>> available for argument passing. >>>> >>>> OK for trunk if there is no regression? >>>> >>>> >>>> H.J. >>>> --- >>>> gcc/ >>>> >>>> PR target/66819 >>>> * config/i386/i386.c (ix86_function_ok_for_sibcall): Allow >>>> indirect sibcall with register arguments if register available >>>> for argument passing. >>>> (init_cumulative_args): Set cfun->machine->arg_reg_available_p >>>> to cum->nregs != 0. > > Please update the above entry for nregs > 0. > >>>> (function_arg_advance_32): Set cfun->machine->arg_reg_available_p >>>> to 0 when setting cum->nregs = 0. >>> >>> Do we also need similar functionality for 64bit ABIs? What happens if >>> we are out of argument regs there? >> >> 64-bit is OK since we have rax, r10 and r11 as scratch registers which >> aren't used to pass arguments. > > Maybe this fact should be added as a comment in some appropriate place. > >>>> * config/i386/i386.h (machine_function): Add arg_reg_available_p. >>>> >>>> gcc/testsuite/ >>>> >>>> PR target/66819 >>>> * gcc.target/i386/pr66819-1.c: New test. >>>> * gcc.target/i386/pr66819-2.c: Likewise. >>>> * gcc.target/i386/pr66819-3.c: Likewise. >>>> * gcc.target/i386/pr66819-4.c: Likewise. >>>> * gcc.target/i386/pr66819-5.c: Likewise. >>>> --- >>>> gcc/config/i386/i386.c | 15 +++++++++------ >>>> gcc/config/i386/i386.h | 3 +++ >>>> gcc/testsuite/gcc.target/i386/pr66819-1.c | 8 ++++++++ >>>> gcc/testsuite/gcc.target/i386/pr66819-2.c | 8 ++++++++ >>>> gcc/testsuite/gcc.target/i386/pr66819-3.c | 10 ++++++++++ >>>> gcc/testsuite/gcc.target/i386/pr66819-4.c | 12 ++++++++++++ >>>> gcc/testsuite/gcc.target/i386/pr66819-5.c | 10 ++++++++++ >>>> 7 files changed, 60 insertions(+), 6 deletions(-) >>>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-1.c >>>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-2.c >>>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-3.c >>>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-4.c >>>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-5.c >>>> >>>> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c >>>> index 54ee6f3..85e59a8 100644 >>>> --- a/gcc/config/i386/i386.c >>>> +++ b/gcc/config/i386/i386.c >>>> @@ -5628,12 +5628,12 @@ ix86_function_ok_for_sibcall (tree decl, tree exp) >>>> if (!decl >>>> || (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl))) >>>> { >>>> - if (ix86_function_regparm (type, NULL) >= 3) >>>> - { >>>> - /* ??? Need to count the actual number of registers to be >>>> used, >>>> - not the possible number of registers. Fix later. */ >>>> - return false; >>>> - } >>>> + /* FIXME: The symbol indirect call doesn't need a >>>> + call-clobbered register. But we don't know if >>>> + this is a symbol indirect call or not here. */ >>>> + if (ix86_function_regparm (type, NULL) >= 3 >>>> + && !cfun->machine->arg_reg_available_p) >>> >>> Isn't enough to look at arg_reg_available here? >> >> We need to check ix86_function_regparm since nregs is 0 if >> -mregparm=N isn't used and pr65753.c will fail. > > OK. Please add this comment, is not that obvious. > >> >>>> + return false; >>>> } >>>> } >>>> >>>> @@ -6567,6 +6567,7 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, /* >>>> Argument info to initialize */ >>>> ? X86_64_REGPARM_MAX >>>> : X86_64_MS_REGPARM_MAX); >>>> } >>>> + cfun->machine->arg_reg_available_p = cum->nregs != 0; >>> >>> false instead of 0. This is a boolean. >> >> Updated. >> >>>> if (TARGET_SSE) >>>> { >>>> cum->sse_nregs = SSE_REGPARM_MAX; >>>> @@ -6636,6 +6637,7 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, /* >>>> Argument info to initialize */ >>>> else >>>> cum->nregs = ix86_function_regparm (fntype, fndecl); >>>> } >>>> + cfun->machine->arg_reg_available_p = cum->nregs != 0; >>> >>> IMO, cum->nregs > 0 would be more descriptive. >> >> Updated. >> >>>> /* Set up the number of SSE registers used for passing SFmode >>>> and DFmode arguments. Warn for mismatching ABI. */ >>>> @@ -7584,6 +7586,7 @@ pass_in_reg: >>>> { >>>> cum->nregs = 0; >>>> cum->regno = 0; >>>> + cfun->machine->arg_reg_available_p = 0; >>>> } >>>> break; >>>> >>>> diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h >>>> index 74334ff..0b6e304 100644 >>>> --- a/gcc/config/i386/i386.h >>>> +++ b/gcc/config/i386/i386.h >>>> @@ -2479,6 +2479,9 @@ struct GTY(()) machine_function { >>>> /* If true, it is safe to not save/restore DRAP register. */ >>>> BOOL_BITFIELD no_drap_save_restore : 1; >>>> >>>> + /* If true, there is register available for argument passing. */ >>>> + BOOL_BITFIELD arg_reg_available_p : 1; >>> >>> This is not a predicate, but a boolean flag. Please remove _p from the name. >> >> Updated. >> >> Here is the updated patch. OK for trunk? > > OK with a small comment additions. > > + /* If true, there is register available for argument passing. */ > + BOOL_BITFIELD arg_reg_available : 1; > + > > Please mention here that this is for 32bit targets only. >
Updated. Is this one OK? Thanks. -- H.J.
From 528ddcbfa2d66c6b34dea88d9ad64593be89159e Mon Sep 17 00:00:00 2001 From: "H.J. Lu" <hjl.to...@gmail.com> Date: Wed, 8 Jul 2015 21:10:25 -0700 Subject: [PATCH] Allow indirect sibcall with register arguments Indirect sibcall with register arguments is OK when there is register available for argument passing. gcc/ PR target/66819 * config/i386/i386.c (ix86_function_ok_for_sibcall): Allow indirect sibcall with register arguments if register available for argument passing. (init_cumulative_args): Set cfun->machine->arg_reg_available to (cum->nregs > 0) or to true if function has a variable argument list. (function_arg_advance_32): Set cfun->machine->arg_reg_available to false if cum->nregs <= 0. * config/i386/i386.h (machine_function): Add arg_reg_available. gcc/testsuite/ PR target/66819 * gcc.target/i386/pr66819-1.c: New test. * gcc.target/i386/pr66819-2.c: Likewise. * gcc.target/i386/pr66819-3.c: Likewise. * gcc.target/i386/pr66819-4.c: Likewise. * gcc.target/i386/pr66819-5.c: Likewise. --- gcc/config/i386/i386.c | 23 +++++++++++++++++------ gcc/config/i386/i386.h | 7 +++++++ gcc/testsuite/gcc.target/i386/pr66819-1.c | 8 ++++++++ gcc/testsuite/gcc.target/i386/pr66819-2.c | 8 ++++++++ gcc/testsuite/gcc.target/i386/pr66819-3.c | 10 ++++++++++ gcc/testsuite/gcc.target/i386/pr66819-4.c | 12 ++++++++++++ gcc/testsuite/gcc.target/i386/pr66819-5.c | 10 ++++++++++ 7 files changed, 72 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-1.c create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-2.c create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-3.c create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-4.c create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-5.c diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 6929caf..0f96452 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -5629,12 +5629,16 @@ ix86_function_ok_for_sibcall (tree decl, tree exp) if (!decl || (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl))) { - if (ix86_function_regparm (type, NULL) >= 3) - { - /* ??? Need to count the actual number of registers to be used, - not the possible number of registers. Fix later. */ - return false; - } + /* Check if regparm >= 3 since arg_reg_available is set to + false if regparm == 0. If regparm is 1 or 2, there is + always a call-clobbered register available. + + ??? The symbol indirect call doesn't need a call-clobbered + register. But we don't know if this is a symbol indirect + call or not here. */ + if (ix86_function_regparm (type, NULL) >= 3 + && !cfun->machine->arg_reg_available) + return false; } } @@ -6610,6 +6614,10 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, /* Argument info to initialize */ if (stdarg_p (fntype)) { cum->nregs = 0; + /* Since in 32-bit, variable arguments are always passed on + stack, there is scratch register available for indirect + sibcall. */ + cfun->machine->arg_reg_available = true; cum->sse_nregs = 0; cum->mmx_nregs = 0; cum->warn_avx512f = false; @@ -6642,6 +6650,8 @@ init_cumulative_args (CUMULATIVE_ARGS *cum, /* Argument info to initialize */ and DFmode arguments. Warn for mismatching ABI. */ cum->float_in_sse = ix86_function_sseregparm (fntype, fndecl, true); } + + cfun->machine->arg_reg_available = (cum->nregs > 0); } /* Return the "natural" mode for TYPE. In most cases, this is just TYPE_MODE. @@ -7584,6 +7594,7 @@ pass_in_reg: if (cum->nregs <= 0) { cum->nregs = 0; + cfun->machine->arg_reg_available = false; cum->regno = 0; } break; diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h index 74334ff..0fcf391 100644 --- a/gcc/config/i386/i386.h +++ b/gcc/config/i386/i386.h @@ -2479,6 +2479,13 @@ struct GTY(()) machine_function { /* If true, it is safe to not save/restore DRAP register. */ BOOL_BITFIELD no_drap_save_restore : 1; + /* If true, there is register available for argument passing. This + is used only in ix86_function_ok_for_sibcall by 32-bit to determine + if there is scratch register available for indirect sibcall. In + 64-bit, rax, r10 and r11 are scratch registers which aren't used to + pass arguments and can be used for indirect sibcall. */ + BOOL_BITFIELD arg_reg_available : 1; + /* During prologue/epilogue generation, the current frame state. Otherwise, the frame state at the end of the prologue. */ struct machine_frame_state fs; diff --git a/gcc/testsuite/gcc.target/i386/pr66819-1.c b/gcc/testsuite/gcc.target/i386/pr66819-1.c new file mode 100644 index 0000000..7c8a1ab --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr66819-1.c @@ -0,0 +1,8 @@ +/* { dg-do compile { target ia32 } } */ +/* { dg-options "-O2 -mregparm=3" } */ +/* { dg-final { scan-assembler-not "call" } } */ + +void foo(void (*bar)(void)) +{ + bar(); +} diff --git a/gcc/testsuite/gcc.target/i386/pr66819-2.c b/gcc/testsuite/gcc.target/i386/pr66819-2.c new file mode 100644 index 0000000..9de4f97 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr66819-2.c @@ -0,0 +1,8 @@ +/* { dg-do compile { target ia32 } } */ +/* { dg-options "-fPIC -O2 -mregparm=3" } */ +/* { dg-final { scan-assembler-not "call" } } */ + +void foo(void (*bar)(void)) +{ + bar(); +} diff --git a/gcc/testsuite/gcc.target/i386/pr66819-3.c b/gcc/testsuite/gcc.target/i386/pr66819-3.c new file mode 100644 index 0000000..3bc5a34 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr66819-3.c @@ -0,0 +1,10 @@ +/* { dg-do compile { target ia32 } } */ +/* { dg-options "-O2 -mregparm=3" } */ +/* { dg-final { scan-assembler-not "call" } } */ + +void (*bar)(int, int); + +void foo(int i, int j) +{ + bar(i, j); +} diff --git a/gcc/testsuite/gcc.target/i386/pr66819-4.c b/gcc/testsuite/gcc.target/i386/pr66819-4.c new file mode 100644 index 0000000..18b2ccf --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr66819-4.c @@ -0,0 +1,12 @@ +/* { dg-do compile { target ia32 } } */ +/* { dg-options "-O2 -mregparm=3" } */ +/* { dg-final { scan-assembler-not "call" } } */ + +#include <stdarg.h> + +void (*bar)(int, va_list); + +void foo(int i, va_list args) +{ + bar(i, args); +} diff --git a/gcc/testsuite/gcc.target/i386/pr66819-5.c b/gcc/testsuite/gcc.target/i386/pr66819-5.c new file mode 100644 index 0000000..6b019d1 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr66819-5.c @@ -0,0 +1,10 @@ +/* { dg-do compile { target ia32 } } */ +/* { dg-options "-O2 -mregparm=3" } */ +/* { dg-final { scan-assembler "call" } } */ + +void (*bar)(int, int, int); + +void foo(int i, int j, int k) +{ + bar(i, j, k); +} -- 2.4.3